Machine gun recharger



Aug. 27, 1946. K. M. HAMMELL 2,406,461

MACHINE GUN RECHARGER Filed Dec. 18, 1943 2 Sheets-Sheet l (DP r" 72INVENTOR. 0% 6/77/61' )7. fiammm-ZZ- Aug. 27,1946. HAMMELL 2,406,461

MACHINE GUN RECHARGER Filed Dec. 18, 1943' 2 Sheets$heet 2 Pr L I 0 8/6!45 IN V EN TOR. Imrper' M H zmme ZZ Patented Aug. 27, 1946 gleam STATESPATENT OFFICIE MACHINE GUN RECHARGER Kemper M. Hammell, Detroit, Mich,assignor to Eureka Williams Corporation, a corporation of 7 Michigan 13Claims.

This invention relates to machine gun rechargers and particularly to anautomatic mechanism for automatically recharging a machine gun in theevent that the bolt thereof fails to retract.

Principal objects of the invention are:

To provide an automatic machine gun recharger;

To provide a new and improved form of automatic machine gun recharger;

To provide a lightweight, efficient, simple and dependable machine gunrecharger adapted to be applied to a machine gun on a plane forautomatically retracting-the bolt thereof when a dead shell is in thebreech of the gun barrel; and

To provide an electrical control circuit fora machine gun rechargeradapted to be attached to a machine gun which is operated under thecontrol of an electric circuit.

Other objects and advantages of the invention will be apparent from aconsideration of the following specification taken in conjunction withthe accompanying drawings, of which there are two sheets and wherein:

Fig. 1 is a side elevational view of a device embodying the invention,with certain parts thereof broken away;

Fig. 2 is a sectional vi w taken generally along the line 22 of Fig. 1,looking in the direction of the arrows;

Fig. 3 is an enlarged view of the switch box and assembly;

Fig. 4 is a diagrammatic illustration of one form of circuit for therecharger; and

Fig. 5 is a diagrammatic illustration of another form of circuit for therecharger.

Referring now to Fig. 1, there is indicated a portion of a machine gunI0 having a bolt l2 which is adapted to reciprocate during the operationof the gun. The bolt I2 is associated with the firing mechanism of thegun and is retracted by the recoil due to the firing of the shell. Whilethese machine guns generally are not operated for more than a fewseconds at a time, there are some which will fire as many as sevenhundred rounds of ammunition per minute, which means that the bolt 52may reciprocate as frequently as approximately twelve times per second.The bolt !2 is indicated in the general position to be released uponclosing of the firing circuit for firing the shell which is positionedin the breech of the gun barrel and after firing of such shell therecoil will move the bolt I2 to the left along the path indicated by theslot 14 of the gun through which the bolt i2 projects.

A-device embodying the invention consists of a mechanism forautomatically retracting the bolt it against the tension of the spring(not shown) thereof if the shell fails to fire, and this mechanism ingeneral comprises a frame i5 adapted to be suitably secured to a machinegun Ill as illustrated in Figs. 1 and 2, said frame forming a supportfor an electric motor [8, a reduction gear 2%], a plurality of sprockets22, 24, and 26, a chain 28 operatively associated with the sprockets, alug 35 on the chain 28, and a switch box 32. In addition to themechanism disclosed in Fig. 1, a circuit such as that illustrated inFigs. 4 or 5 is employed in connection therewith, and such circuitsinclude certain control mechanism which may be mounted in a box or on apanel elsewhere than on the recharger itself.

The sprocket 22 is mounted on a shaft 35 which projects from thereduction gear 23. The reduction gear 20 may comprise a suitable housinghaving gearing therein connected to the shaft of the motor i8 and driventhereby, the gearing functioning to drive the shaft 34 at a speed muchless than that of the motor during the operation thereof. The teeth ofthe sprocket 22 operatively engage the links of the endless chain 28 fordriving the same, the sprockets Ed and 26 supportingthe chain so that ithas a path of movement parallel to the path of movement of the bolt iii.The lug 30 is carried by the chain and has a shoulder 36 which when thechain is driven in the direction indicated by the arrow 98 is adapted tomove through a path so as to engage the bolt 62 at the right hand end ofslot M and move it to the left for the purpose of retracting the sameagainst the sprin which is conventionally associated therewith.

The lug 39 at one end thereof is pivoted at 38 to the chain, and at theother end thereof has a pin and slot connection M] with the chain so asto not interfere with the passage of the chain over the sprockets. Whenthe 111;; 33 has moved the bolt i2 to its leftmost or retracted position(approximately the lefthand end of the slot I l) the path of the lug 3i:veers away from the path of the bolt [2 so as to disengage the lug 30from the bolt 12, thereby permitting the spring associated with the boltto return it in order to fire the shell in the breech of the gun.

The frame It may be suitably formed of sheet metal and have suitablebrackets by means of which the reduction gear 29, the motor l8 andswitch box 32 may be assembled to the frame l6 itO form a unit, and theunit may be assembled tothe machine gun Iii in the relative positionindicated. Cover or guard 5 1 may be removably secured to the frame l6so as to at least partially enclose the operating mechanism of the unit.

The sprockets 24 and 26 are each individually journaled on a bearing 58which is carried by an eccentric sleeve 58 which in turn is carried byscrew 6!] which in turn is threaded into nut 62 carried by the frame it.Thus the sprockets 24 and 26 may each be adjusted vertically orhorizontally and independently of each other so as to properly positionthe chain 28 and tension the same.

The switch box 32 has arranged therein a double contact switch 64 whichwill hereinafter sometimes be referred to as a bolt-operated switch, andanother switch 68 which will hereinafter sometimes be referred to as achain-operated switch. The bolt-operated switch 64 includes stationarycontacts 88 and movable contacts ill, the contacts 18 being carried by amember which is mounted on a pin or plunger 12. Plunger 12 isreciprocally mounted in the switch box 32 and the righthand end thereof,as illustrated in Fig. 1, is positioned so as to be engaged by the boltl2 at the end of each retractile stroke thereof. A spring M arrangedaround one end of the plunger 12 and confined between one wall of thecase 32 and the movable contacts IE1 biases the same out of engagementwith the stationary contacts 68 so that the bolt switch 94 is normallyopen.

The stationary contacts 68 preferably are resiliently mounted. A spring76 may be arranged between the member which carries the movable contactsHi and a nut F8 secured to the plunger which cooperates with bracket 80so as to limit the movement of the plunger 12 to the right. The plunger72 extends through a suitable hole in bracket 8!]. The member whichcarries the movable contacts 19 is not fastened on the plunger 12 but ispositioned thereon by the springs 1 and 15. When the bolt l2 strikes theend of the plunger 12 and thereby moves the same to the left, the switch64 will be closed for a fraction of a second. The actual time intervalthat the switch 64 is closed will to some extent depend upon the speedof firing of the machine gun. Under some circumstances it may bedesirable to provide some means to retard slightly the opening movementof the switch 64.

Switch 66 includes movable contact 82 and stationary contact 84. Thisswitch is normally open and is adapted to be closed and opened by thechain during each cycle of movement. Movable contact 82 is carried by aswitch-operating member 85 having arms 88 and 9B. The member 86 in crosssection is U-shaped, and the arm 88 is positioned at one side of thechain 28 while the other arm 99 is positioned on the opposite side ofthe chain 28. The member 86 is pivoted at 92 and is held in either itsopen or closed position by a spring 9 3, one end of which bears againstthe end of the member 86. For example, in the position illustrated, theend of the spring 94 bears against the member 86 to one side of thepivot 92, thereby holding the same in its open position. When the switchis closed the member 86 pivots in a counterclockwise direction, therebyshifting the end of the spring 94 to the other side of the pivot 92 forholding the switch 66 closed. The switch arm 90 is, in the position inwhich it is illustrated, arranged in the path of a pin 96 which projectslaterally from one of the links of the chain. The pin 96 projects towardthe machine gun and after the chain has moved a limited 4 amount in itsdriven direction, which is indicated by the arrow 98, the pin 96 willengage the arm 9i] and shift the member 86 to its other position so asto close the switch 66.

The chain 28 is provided with another laterally extending pin H33 whichprojects from one of the links of the chain in a direction way from thegun and which pin 569 is adapted to engage the arm 88 and return themember to the position illustrated in Fig. 1 so as to open the switch68. Thus, after the chain 23 and lug 39 have been moved a small amountfrom their starting position in which they are indicated in Fig. 1, thepin 96 will by acting on the switch arm close the chain-operated switch86, and shortly before the chain 28 and lug 38 are returned to theirstarting position the pin Hit will engage the switch arm 88 and open theswitch 66. After the switch 66 is open the inertia of the motor [8 andgearing 251 will permit the lug 31! to return approximately to theposition illustrated.

The bolt-operated switch (it is adapted to be closed during theoperation of the machine gun by the reciprocation of the bolt l2, andthe closing of the switch 64 controls the motor circuit so as to preventthe operation thereof while the machine gun is operating, if the triggerand safety switches thereof are closed as will be further describedhereafter. However, should the machine gun fail to operate with thetrigger switch and safety switch closed, the bolt i2 will notreciprocate and the switch 64 will remain open, thereby controlling thecircuit of the motor so as to initiate the operation thereof. When themotor operates, the chain 28 will be driven in the direction indicatedby the arrow 98 and after a relatively small movement of the chain theswitch 66 will be closed. The switch 66 controls the motor circuit so asto keep the same closed after the motor begins to operate and until therecharger mechanism completes one cycle of operation.

One cycle of operation consists of movement of the chain 23 sufiicientlyso as to move the lug 30 from the position in which it is illustrated inFig. 1 around past the sprockets 26, 24 and 22 and back to the positionillustrated. During this movement the lug 30 will, as previouslydescribed, retract the bolt l2 and free it for movement under influenceof its spring. The switch 66 closes the motor circuit shortly after themotor begins to operate and will keep the motor circuit closed untilopened by the pin I00, even though the trigger and/or safety switch ofthe machine gun circuit are opened before the mechanism completes onecycle of operation.

The wires of the motor circuit are connected to the switches in theswitch box 32, and the switches in the switch box 32 are adapted to beconnected by suitable current conductors to the controls, the connectorIll] being provided on the switch box 32 for cooperation with a suitableconnector on the current conductors which lead to the controls.

The switches and controls and circuits are diagrammatically illustratedin Fig. 4 wherein the same reference characters have been employed toindicate the switches as described in connection with Fig. 1. ConductorA is connected by the master gun or safety switch HI of the firingcircuit for the machine gun to a suitable source of current, and whensuch switch is closed the conductor A is energized. This conductor A isconnected to one side of the motor l8 and a conductor B leads from theother side of the motor I8 to contact 84 of switch 66. This conductor Bis adapted to be grounded by the switch 86 when the same is closed so asto close the circuit through the motor. The conductor B is alsoconnected to one of the stationary contacts of a double contact relayswitch H4. The other stationary contact of switch H4 is grounded. Themovable contact or armature H6 of relay switch H4 is positioned so thatthe switch H4 is normally closed when the safety switch III is open.Whenever the conductor B is grounded, either through switch 66 orthrough switch H4, the motor will operate. The conductor A is connectedto one end of the coil H8 of the relay of switch H4, while the "otherend of V such coil is connected by conductor C to the firing circuit Dwhich includes the firing solenoid H5. A 28-volt, l3-watt lamp I23 isarranged in series with relay coil H8 and between the same and conductorC.

As the switch H4 is closed when the safety switch I I I is open, thecircuit through the motor I8 will be closed upon closing of the switchIII, but as the coil of relay switch H4 is arranged in parallel with themotor I8 and grounded through the firing circuit D and solenoid H5, therelay will act immediately to open switch H4. While the circuit throughthe motor I8 is closed momentarily, such circuit is not closed for asufficient length of time to enable the motor to do any more than turnthrough several degrees of movement. The coil H8 of the relay preferablyhas a voltage rating of 4 volts, much less than the rating of the motorcircuit which may be 18-28 volts, so that the relay H8 will be excitedquickly in order to open the switch H4 very quickly after the safetyswitch I I I is closed. The resistance of the lamp I28 when the same iscold is comparatively low, but this resistance increases rapidly andconsiderably when the lamp is lighted, thereby protecting the relay H8from overload.

When the trigger switch IE3 is closed the machine gun firing circuit Dwill be closed, thereby actuating the solenoid H5 to release the firingpin thereby initiating the operation of the ma-- chine gun. When thetrigger switch I I3 is closed, both ends of the relay coil H3 will beconnected through conductors C and A to the positive side of thecircuit, thereby tending to neutralize or deenergize the coil I I8.However, as soon as the firing solenoid H5 is actuated, the gun beginsfiring and the bolt I2 thereof will engage the movable contact of switch54 and close the same momentarily, thereby grounding the coil H8 andconductor C through conductor E and switch 64. The relay switch H4 is ofthe delay type and is adapted to be energized rapidly relative to itstime of deenergization. A timing slug I I1 is pro- Vicled on relay H8 todelay the drop out thereof. That is, during the time that thebolt-operated switch 54 is closed, which may be for .005-.010 second percycle, the relay coil H8 must be excited sufilciently in order to holdswitch I I4 open until the next cycle of excitation, and thecharacteristics of the relay coil H8 must be such that approximately ofa second must elapse after the circuit through the relay is openedbefore the armature HE is released. Because of this the switch H4 willremain open during the reciprocation of the bolt I2. As soon as suchreciprocation stops the relay coil I I8 will become deenergized andpermit the closing of switch H4,

thereby closing the circuit through the motor I8 and initiating theoperation thereof. A defective shell in the breech of the machine gun isusually the cause for the failure of the bolt I2 to reciprocate.

The switch 66 will be closed as previously described shortly after themotor begins operating and will remain closed until shortly before thelug 38 completes one cycle of operation. Thus if the trigger switch isopened, which would deenergize the conductor 0, the motor circuit wouldbe closed from conductor A through the switch 66, and in this way therecharger mechanism will complete a cycle, once started, irrespective ofwhether or not the trigger switch is open during a cycle, so that thenext time that the trigger switch is closed the machine gun will becooked for immediate firing.

Thus one form of my invention comprises a recharger for an electricallyoperated machine gun I0 adapted to be fired by the closing of a firingcircuit D, said circuit including a master switch III, a firing switchH-3 and a firing solenoid H5, said firing switch being in series withsaid master switch and operable upon closing, when said master switch Hiis closed, to energize said firing solenoid H5, thereby to initiate thenormal operation of the machine gun (assuming that the gun is loaded andprovided with means such as a cartridge belt for supplying liveammunition thereto), said gun having a reciprocable bolt I2 adapted tobe retracted normally by the recoil of a fired shell, said rechargercomprising a member 38 movable through a path and in its movementthrough said path being engageable with said bolt I2 for retracting thesame and being adapted to release said bolt in its retracted position,an electric motor I8, a driving connection between said motor and member38 for moving the latter through its path during operation of saidmotor, a motor circuit A, B having its high potential end connected tosaid firing circuit D between said switches, a time delay relayincluding a switch H4 associated with the grounded end B of the motorcircuit and operable to open the motor circuit upon closing of saidmaster switch III, one end of the relay coil H8 being connected to thehigh potential end A of the motor circuit, the other terminal of therelay coil I I8 being arranged, upon closing Of said master switch III,to be grounded through a lamp bulb I28 in series with said firingsolenoid H5, when said firing switch H3 is open, for operating saidrelay switch H4 to open said motor circuit, said other terminal of saidrelay coil H8 also being arranged to be grounded through a bolt-operatedswitch 64, periodically momentarily closed by and during thereciprocation of said bolt I2, (during normal operation of said gun)when the firing switch H3 is closed, for energizing said relay coil H8sufi'iciently to keep said switch I I4 from closing, thereby to keepsaid motor circuit AB open, a mechanically operated switch 66 adapted tobe closed by the cycling of said member 30 and arranged upon closing toground said motor circuit AB, the voltage rating of said relay coil H8being materially less than that carried by said motor circuit AB and theinitial resistance of said lamp bulb I28 being Suificiently low so thatupon closing of said master switch III, the relay coil H8 will beenergized at 'a sufiiciently rapid rate so that the relay switch H4 willopen the motor circuit before the motor makes an appreciable startingefiort, the characteristics of the lamp bulb I28 being such that uponlighting, the resistance thereof increases thereby limiting the currentin the relay coil "7 H8 to a safe value, the closing of said firingswitch I I3 functioning to energize the firing solenoid H and todeenergize said relaycoi1.II8 and lamp bulb I 20, the operation of saidmachine gun and reciprocation of the, bolt I2 thereof pursuant to theenergization of solenoid I I5 functioning to periodically close saidbolt-operated switch 64 sufficiently frequently to maintain said coilIE8 energized sufficiently to maintain said relay switch II 4 open, saidtime delay relay being constructed to allow a rapid opening of the relayswitch. I I4 and a relatively slow closing thereof, the period of theclosing time of said relay being appreciably greater than the period ofoperation of the machine gun, the coil II8 of the relay being wound soas to have asufliciently low impedance that a sufiiciently highexcitation will be produced in the coil upon the periodic momentaryclosing of the bolt operated switch, failure of said gun to operate whensaid firing switch is closed deenergizing the coil H8 of said relay andpermitting said switch M4 to close said motor circuit thereby initiatinga cycle of operation of said recharger to effect the. retraction of saidgun bolt, said mechanically operated switch being closed by the cyclingof said memebr 30, to keep said motor circuit closed until saidrecharger completes said cycle of operation, said member being operableduring said cycle of recharger operation to retract said bolt and freethe same, in order to restart the operation of said machine gun if saidfiring switch H3 and motor switch III are closed, restarting of theoperation ofsaid-machine gun causing the bolt I2 thereof to close saidboltoperated switch 64 to ground said relay coil H8 in order to keepopen said motor circuit after said recharger has completed one cycle ofoperation.

In the modified form of the invention using the circuits illustrated inFig. 5, in lieu of that illustrated in Fig. 4, the machine gun isadapted to be fired by the closing of firing circuit D, said circuitincluding master switch III, firing switch I I3 and firing solenoid II5, said firing or trigger switch being in series with said masterswitch and operable upon closing, when said master switch III is closed,to energize firing solenoid H5, thereby to initiate normal operation ofthe machine gun (assumingthat the'gun is loaded and provided with meanssuch as a cartridge belt for supplying live ammunition thereto) andreciprocation of the bolt I2 thereof. I

The motor I8 is operatively arranged in a motor circuit FG having itshigh potential end connected to the firing circuit D between switchesIII and H3. Certain parts of these circuits duplicate parts of thecircuits illustrated in Fig, 4 and in such cases the same referencecharacters as used in Fig. 4 have been employed in Fig. 5 to designatecorresponding parts. The motor circuit is adapted to be grounded throughrelay switch 30 or through the mechanically operated switch 66, which aspreviously indicated is normally open, but closed during cycling of therecharger. Relay switch I30 form par-t of a time delay relay means whichincludes a low impedance circuit I32 and a normal impedance circuit I34connected in parallelto the high potential side of the motor circuit.Low impedance circuit I32 includes a relay coil I36 (which may have aresistance of 1.4 ohms) which is arranged in series with coil I38 (whichmay have a resistance of 200 ohms) of the normal impedance circuit I34.Lowimpedance circuit I32 is'ada'pted to .begrounded either throughbolteoperat'ed switch Switch 64.

6'4, periodically momentarily closed by and 'during the'reciprocation ofbolt I2, (during normal operation of the machine gun) or throughserially arranged switches I and I42. Switche I30 and I40 aresimultaneously opened by energize.- tion of coil I33 and circuit I32,which occurs (starting with the. circuits arranged as illustrated)immediately upon energization of the motor circuit FG due to the closingof master switch III. Thus the low impedance circuit I32 is energizedonly momentarily. Normal impedance circuit I34, arranged in parallelwith circuit I32, is energized simultaneously therewith being groundedthrough switch I 4-4, the energization of coil I38 functioning to keepswitches I33'and I40 open after. the low impedance circuit is opened.-As

thus arranged the circuits are in what might be .firing solenoid I I5,thereby initiating operation of the machine gun. If live ammunition i inthe gun, the gun will operate thereby causing reciprocation of bolt I2,which in turn will periodically momentarily close switch 54. The closingof the firing circuit D will also energize the circuit Kin which switchI46 (now closed) is arranged, circuit K having its high potential sideconnected to the firing circuit D and being grounded through pullin coilI48 (100.chms) of. a-control relay means which further includes lock-incoil I (240 ohms) and switches. I42 and I44. Energization of coil I48will open switches I42 and I44, thereby opening the normal impedancecircuit I34 and deenergizing coil I38(low impedance circuit I32previously having been'deenergized by opening of switch I40). The coilI43 operates to open switches I42 and I44 before the bolt I2 closesswitch 64, but the coils I36 and I38 of the time delay relay areprovided with a timing slug or means I52 Which'holds open the switchesI30 and I4!) until the low impedance circuit is grounded through thebolt-operated switch 64; that is, the timing slug I52 delays thedeenergization of coil I33 for a period of time (a fraction of a second)until the coil I36 is energized by the closing of The coils I36 and I33of thetime delay relay are constructed to allow a rapid opening of therelay switches I30 and I 40 and a relatively slow closing thereof, theperiod of the 010sing time of the relay being appreciably greater thanthe period of operation of the machine gun. The grounding of the lowimpedance circuit I32 through the bolt-operated switch 64 functionsduring normal operation of the machine gun to keep the pull-in coil I36energized sufliciently to keep the switches I 30 and I40 open and theswitch I46 closed.

So long as the switches 63 and I30 are open, the motor circuit FG willbe open, and this condition will prevail during normal operation of themachine gun. If after closing of the trigger switch I I3, the gun failsto start or stops, the boltoperated switch 64 will remain open, therebydeenergizing the low impedance circuit I32, as a result of which thecoil I36 of the time delay relay will become deenergized, therebyallowing switches I33 and I40 to close and switch I46 to open. Theclosing of switch I30 will close the motor circuit FG, therebyinitiating operation of the motor which, through the mechanismpreviously described, will retract the'bolt I2, as a consequence ofwhich a new piece of ammunition will be inserted in the gun barrel forfiring.

The switches of the time delay relay are set so that the switches I30and I40 will close before switch I46 opens. The closing of switch I40will close the low impedance circuit I32 and ground the same through thelock-in coil I50. The resulting energization of the lock-in coil I50will function to keep the switches I42 and I 44 open even though thecoil I48 might become deenergized due to the opening of the switch H3 orswitch I46. The lock-in coil I50 has a resistance of about 240 ohms sothat when the low impedance circuit I32 is grounded through such coilI50, the latter will draw practically all of the current in the circuit,with the result that the coil I35 will not be energized sufiiciently toopen the switches I30 and I40 or to close the switch I 45. Between theswitch E30 and the ground, a resistance I 60 of one ohm is provided inorder to reduce the load across the contacts of the switch I 30 duringthe opening and closing thereof. When the switch I30 closes, theoperation of the motor will be initiated to begin the cycling of therecharger, but as hereinafter explained the motor will be operated undersubstantially no load until after the chain-operated switch 55 closes,which occurs as soon as the chain 28 has moved sumciently to engage andactuate the switch arm 90 by the pin 96.

Toward the end of the cycle of operation of the recharger the pin Iwill, through engagement with the arm 88 of the switch 66, open the sameafter the recharger has been relieved of the load of the bolt I2. Theretraction of the bolt I2 by the recharger will close the switch 54before the switch 66 is opened as just described. Such closing of theswitch 54 will thereby close the circuit through the low impedance coilI36, thereby energizing the same to open the switches I30 and I40 andclose the switch I46, such switch I46 closing before the switches I30and I40 open. While the lock-in coil I50 will be deenergized by theopening of switch I 40, the previous closing of switch I46 will closethe circuit K through the pull-in coil I48. As a result of the foregoingactions following the closing of the switch 64 by the bolt I2 upon theretraction thereof by the recharger, the circuits will be restored totheir stand-by position. If the new shell injected into the gun barrelis a piece of live ammunition, the normal operation of the gun will beresumed with the result that the bolt I2 will periodically momentarilyclose the switch 54. thereby closing the low impedance circuit I32sufficiently frequently to keep the coil I 36 energized in order to keepthe switches I30 and I40 open and the switch I46 closed. It will beobserved that the motor circuit is closed through the switch 65 in orderto permit the recharger to complete its cycle of operation and that theopening of firing switch I I3 during a cycle will not interfere with thecompletion thereof. The opening of switch I46 will prevent an inductivereactance f om the firing solenoid II5 from momentarily deenergizing thecoil I48 of the control relay under certain conditions.

While the circuits disclosed herein form a part of a rechargermechanism, I contemplate that such circuits may be employed in othertypes of cyclic mechanisms for restarting the operation thereof. In itsbroadest aspect the invention disclosed and claimed herein comprises amechanism operable at a substantially constant cyclic rate (the machinegun), electric means (the firing solenoid H5 and circuit therefor) toinitiate operation of such mechanism, restoring means electricallyoperated and mechanically operable (the motor driven member toreestablish motion in said mechanism when said cyclic rate isinterrupted due to accidental cause, electrical discriminating means(the time delay relay and the low impedance circuits) actuated at leastonce per operating cycle of said mechanism and operable to initiatefunctioning of said restoring means, interlocking means (lock-in coilI50, switches I42 and 144, and the chain operated switch 65) associatedwith said discriminating means and operable to cause the completion ofthe cycle of the restoring means once the discriminating means hasinitiated operation thereof, and unlocking means (switch 54, coil Iwhich operate when the bolt I2 is retracted by the member 30 to causethe deenergization of the lock-in coil I and the opening of switch I42)associated between said discriminating and interlocking means andoperable to restore said discriminating and interlocking means to astand-by condition.

If the coil I48 is provided with some time delay action to delay thedrop-out thereof, then it becomes immaterial whether the switch I46closes before the switches I30 and I40. This time delay for the coil I48may be obtained by utilizing a timing slug, such for example, as thetype employed in connection with the coil I 38 as indicated by thereference character I52.

While the invention has been described with some detail, it is to beunderstood that the description is for the purpose of illustration onlyand is not definitive of the limits of the inventive idea. The right isreserved to make such changes in the details of construction andarrangement of parts as will fall within the purview of the attachedclaims.

I claim:

1. A recharger for an electrically controlled machine gun adapted to befired by the closing of a firing circuit, a trigger switch operable forclosing said firing circuit, said machine gun having a reciprocable boltadapted to be retracted normally by the recoil of a fired shell, saidrecharger comprising a member movable through a cycle and in itsmovement through said cycle being engageable with said bolt forretracting the same and being constructed and arranged to release saidbolt in its retracted position in order to restart the operation of saidgun if said firing circuit is closed, an electric motor, a drivingconnection between said motor and member for moving the latter throughits cycle during operation of said motor, an electric circuit in whichsaid motor is included, a relay including a switch in said motor circuitand a coil, one side of said coil being connected to the high potentialside of said motor circuit, said coil upon being energized functioningto open said switch in said motor circuit, the closing of said firingcircuit by said trigger switch functioning to initiate the operation ofthe machine gun and the reciprocation of said bolt, means operable uponthe closing of said firing circuit to deenergize said coil, the drop outtime of said relay coil being greater than the period of reciprocationof said bolt, and means including a circuit for said coil having anormally open switch provided with an actuating member positioned in thepath of said bolt and constructed and arranged to be actuated therebynormally to close said switch momentarily and periodically during thereciprocation of said bolt for energizing said relay coil-sufficientlyfrequently to keep said relay switch open, failure of said gun tooperate when said trigger switch is closed causing the deenergization ofsaid coil and the resultant closing of said motor circuit, thereby toinitiate a cycle of operation of said recharger to efiect the retractionof said gun bolt.

2. The construction defined in claim 1 in which a safety switch isprovided in said firing and motor circuits for opening the same. 7

3. The construction defined in claim 1 in which means are provided tokeep the motor circuit closed if the firing circuit is deenergizedbefore the recharger has completed said cycle of operai tion.

4. A recharger for an electrically controlled machine gun adapted to befired by the closing of a firing circuit, a trigger switch operable forclosing said firing circuit, said machine gun having a reciprocable boltadapted to be retracted normally by the recoil of a fired shell, saidrecharger comprising a member movable through a cycle and in itsmovement through said cycle being engageable with said bolt forretracting the same and being constructed and arranged to release saidbolt in its retracted position in order to restart the operationof saidgun if said firing circuit is closed, an electric motor, a drivingconnection between said motor and, member for moving the latter throughits cycle during operation of said motor, an electric circuit in whichsaid motor is included, a relay including aswitch in said motor circuitand a coil, one side of said coil being connected to the high potentialside of said motor circuit and the other side of said coil.

being grounded through said firing circuit when said trigger switch isopen, said coil being energized immediately upon the closing of saidmotor circuit, to open said switch in said motor circuit, the closing ofsaid firing circuit by said trigger switch functioning to initiate theoperation of the machine gun and the reciprocation of said bolt, meansoperable upon the closing of said firing'circuit to deenergize saidcoil, the drop out time of said relay being greater than the period ofreciprocation of said bolt, and means including a circuit for said coilhaving a normally open switch therein provided with an actuating memberpositioned in the path of said bolt and constructed and arranged to beactuated thereby normally to close said switch momentarily andperiodically during the reciprocation of said bolt for energizing saidrelay coil sufficiently frequent- 1y to keep said relay switch open,said relay switch operating to close said motor circuit upon failure ofsaid bolt to reciprocate when said firing circuit i closed.

5. The construction defined in claim 4 in which closed if the firingcircuit is opened before the motor has driven said member through acomplete cycle. V

6. The construction defined in claim 4 in which a safety switch isprovided in said firing and motor circuits for opening the same.

7. A recharger for an electrically controlled machine gun adapted to befired by the closing of a firing circuit, a trigger switch operable forclosing said firing circuit, a safety switch in said firing circuitahead of said trigger switch, said machine gun having a reciprocablebolt adapted to be retracted normally by the recoil of a fired shell,said recharger comprising a member movable through a, cycle and in itsmovement through said cycle being engageable with said bolt forretracting the same and being constructed and arranged to release saidbolt in its retracted position in order to restart the operation of saidgun if said switches are closed, an electric motor, a driving connectionbetween said motor and memher for moving the latter through its cycleduring operation of said motor, an electric circuit in which said motoris included, the high potential side of said motor circuit beingconnected to said firing circuit between said switches, a time delayrelay having a'switch in said motor circuit and a coil, one side of thecoil of said relay being connected to the high potential side of saidmotor circuit, said coil being energized by the closing of said safetyswitch immediately to open said relay switch in the motor circuit, theclosing of said firing circuit by said trigger switch functioning toinitiate the operation of the machine gun and the reciprocation of saidbolt, means operable upon the closing of said firing switch todeenergize said coil, the drop out time of said relay coil being greaterthan the period of reciprocation of said bolt, means including a circuitfor said coil having a normally open switch therein provided with anactuating member positioned in the path of said bolt and constructed andarranged to be actuated thereby normally to close said switchmomentarily and periodically during the reciprocation of said bolt forenergizing said relay coil sufiiciently frequently to keep said relayswitch open, failure of said gun to operate when said trigger and safetyswitches are closed causing the deenergization of said coil and theresultant closing of said motor circuit, thereby to initiate a cycle ofoperation of said recharger to efi'ect the retraction of said gun bolt.

, 8. The construction defined in claim 7 in which shell, said rechargercomprising a member movable through a cycle and in its movement throughsaid cycle being engageable with said bolt for retracting the same andbeing constructed and arranged to release said bolt in its retractedposition in order to restart the operation of said gun if said firingcircuit is closed, an electric motor, a driving connection between saidmotor and member for moving the latter through its cycle duringoperation of said motor, an electric circuit in which said motor isincluded, a time delay relay having a switch in said motor circuit and acoil, one side of the coil of said relay being connected to the highpotential side of said motor circuit and the other side of said coilbeing grounded through said firing circuit when said trigger switch isopen, an electric lamp in series with said coil and arranged in theconnection between said coil and said firing circuit, said on theclosing of said firing switch to deenergize said coil, the drop out timeof said relay being greater than the period of reciprocation of saidbolt, and means including a circuit for said coil having a normally openswitch therein provided with an actuating member positioned in the pathof said bolt and constructed and arranged to be actuated therebynormally to close said switch momentarily and periodically during thereciprocation of said bolt for energizing said relay coil sufiicientlyfrequently to keep said relay switch open, said relay switch operatingto close said motor circuit upon failure of said bolt to reciprocatewhen said firing circuit is closed, and means to keep the motor circuitclosed if the firing circuit is opened before the motor has driven saidmember through a complete cycle, said'last-mentioned means comprising acircuit for said motor circuit having a normally open switch thereinprovided with an actuating member engaged and actuated by a part of saidbolt engaging member at the beginning of said cycle for, closing saidmotor circuit and at the end of said cycle for opening said motorcircuit.

10. A recharger for an electrically controlled machine gun adapted to befired by the closing of a firing circuit, a trigger switch operable forclosing said firing circuit, a safety switch in said firing circuitahead of said trigger switch, said machine gun having a reciprocablebolt adapted to be retracted normally by the recoil of a fired shell,said recharger comprising a member movable through a cycle and in itsmovement through said cycle being engageable with said bolt forretracting the same and being constructed and arranged to release saidbolt in its retracted position in order to restart the operation of saidgun if said switches are closed, an electric motor, a driving connectionbetween said motor and member for moving the latter through its cycleduring operation of said motor, an electric circuit in which said motoris included, a time delay relay including a coil and a switch associatedwith the motor circuit and operable to open the motor circuit, one endof the coil of said relay being connected to the high potential end ofthe motor circuit, the other terminal of the relay coil being arrangedto be grounded through a lamp bulb in series with the firing circuitwhereby said relay switch may operate to open said motor circuit, saidother terminal of said relay coil also 'H' being arranged to be groundedthrough a bolt operated switch periodically momentarily closed by andduring the reciprocation of said bolt for energizing said relay coilsufiiciently to keep said relay switch from closing thereby to keep said:1

motor circuit open, the electrical rating of said relay coil beingmaterially less than that of said motor circuit and the initialresistance of said lamp bulb being sufficiently low so that upon closingOf the relay circuit, the coil will be energized at a rapid rate to openthe motor circuit, the characteristics of the lamp bulb being such thatupon lighting, the resistance thereof increases thereby limiting thecurrent in the relay coil to a safe value, the closing of the firingswitch functioning to energize the firing circuit and to deenergize saidrelay coil and lamp bulb, said time delay relay being constructed toallow a rapid opening of the relay switch and a relatively slow closingthereof, the period of the closing time of said relay being appreciablygreater than the period of operation of the machine gun, the coil ofsaid relay being wound so as to have a suificiently low impedance that asufficiently high excitation will be produced in the coil upon theperiodic momentary closing of said bolt operated switch, failure of saidgun to operate when said firing switch is closed deenergizing the coilof said relay and permitting said relay switch to close the motorcircuit thereby initiating a cycle of operation of said recharger toefiect the retraction of said gun bolt.

ll. The construction defined in claim 10 in which a mechanicallyoperated switch is provided for closing the motor circuit, saidmechanically operated switch being closed by and during the cycling ofthe recharger.

12. A. recharger for an electrically controlled machine gun adapted tobe fired by the closing of a circuit, a trigger switch operable forclosing said firing circuit, a safety switch in said firing circuitahead of said trigger switch, said machine gun having a reciprocablebolt adapted to be retracted normally by the recoil of a fired shell,said recharger comprising a member movable through a cycle and in itsmovement through said cycle being engageable with said bolt forretracting the same and being constructed and arranged to release saidbolt in its retracted position in order to restart the operation of saidgun if said switches are closed, an electric motor, a driving connectionbetween said motor and member for moving the latter through its cycleduring operation of said motor, an electric circuit in which said motoris included, said motor circuit being arranged to be closed through aswitch of a time delay relay means when the safety switch is closed,said time dela relay means including a low impedance circuit, a normalimpedance circuit connected to the high potential side of said motorcircuit and a coil, the coil of said relay comprising a low impedancecoil in said low impedance circuit and a normal impedance coil in saidnormal impedance circuit, said low impedance circuit further including aswitch constructed and arranged to be opened simultaneously with saidrelay switch in said motor circuit by energization of said low impedancecircuit, a fire control relay including a switch for closing said lowimpedance circuit and a lock-in coil through which said low impedancecircuit may be grounded when said last-mentioned switch is open, saidlow impedance coil functioning to open the low impedance circuit and themotor circuit immediately upon the closing of said safety switch, saidcontrol relay further including a switch in said normal impedancecircuit for closin the same so as to energize said normal impedancecoil, said last-mentioned coil functioning to keep said switches of saidtime delay relay in said motor and low impedance circuits open, saidcontrol relay including a pull-in coil which is arranged in a circuitthat is energized upon the closing of said firing switch, said pull-incoil functioning to open the switches of said control relay so as toopen the normal impedance circuit, a bolt operated switch constructedand arranged upon closin to close the low impedance circuit, said boltoperated switch being constructed and arranged to be e closedperiodically momentaril by the reciprocation of the bolt during thenormal gun operation, means to prevent the deenergization of the coilsof said time delay relay after opening of the normal impedance circuitand before said low impedance circuit is closed through said boltoperated switch, the drop out time of said time delay relay beinggreater than the period of reciprocation of said bolt, closing of saidbolt operated switch functioning to energize the low impedance coilsufficiently frequent to keep said relay switch operate when saidtrigger and safety switches are.

closed permitting the deenergization of the coil of said time delayrelay and the closing of said relay switch in said motor circuit. 7

13. The construction defined in claim 12 in Which the deenergization ofthe low impedance circuit permits the closing of the low impedancecircuit through the lock-in coil of the control relay so as to keep themotor circuit closed during 10 thecy'cling of the recharger, theresistance of the:

low impedance coil being materially less than that of the lock-in coilof the control relay so that when the low impedance circuit is groundedthrough said lock-in coil said low impedance coil will not be energizedsuficiently to open the switches of the time delay relay in either ofthe motor or low impedance circuits.

KEMPER M. HAMMELL.

